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  • Few position reports ?!?

    Hi there,

    I have only feed FR24 for a few days. And the first day I had about 40k hits reported, and about 22,5k positions reported (a bit more than 50% positions reports vs. hits reports). Day two was a bit less than 50% position reports vs. hits reports. And it has become severely worse. Today I have about 29.1k positions reported, but only about 4000 positions reported ?!? My feeder is named T-ENNO9 if you want to look at the numbers.

    Is there any reason why there is so few position reports ? A friend of mine is living a few hundred meteres away. He has only a indoor antenna, and of course a lower range than me, and also fewer position reports (SIGNIFICANTLY fewer). But today he has more positions reported than me. Why ?

  • #2
    The server can pick and choose its sources if there are many with the same hits. And make the other drop them to save data overlap

    If you view the logs you see this as 'x ignored'

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    Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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    • #3
      That is not correct as far as i'm aware. Density of feeders should have no effect on the stats.

      You are looking at a very limited area of the sky and today is Sunday which means less traffic and maybe different flight patterns.
      For example there could be more planes flying that don't send a position. Thus hits would be more and positions would be less.

      Also just because the antenna is outdoors doesn't mean it has a good view of the sky. If you stand where the antenna is, if you couldn't see the airplane with your eyes you can probably not receive it as it needs a direct line of sight.

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      • #4
        Different flight patterns etc. would affect all the receivers in the area in (more or less) the same way. But mine is the only one affected. Actually, my radar is the one (from all the ENNO receivers which have stats available) with the most "hits reported". But at the same time the one with the fewest "positions reported". And this has become progressively worse since I started feeding.

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        • #5
          Positions reported are full adsb with GPS Enabled data. No t everything has one as pointed out. Most/modeS only are excluded from that.

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          Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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          • #6
            Originally posted by wiedehopf View Post
            That is not correct as far as i'm aware. Density of feeders should have no effect on the stats.
            The stats were meant to reflect what the clients range etc is too. But we all know how accurate and similar to local data that can be....


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            • #7
              Skjermbilde 2019-01-27 kl. 23.16.20.jpg

              The position is 18.5S old in this screenshot, but the aircraft says "hello" every second.

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              • #8
                Originally posted by Talle View Post
                [ATTACH=CONFIG]10204[/ATTACH]

                The position is 18.5S old in this screenshot, but the aircraft says "hello" every second.
                Looking at those tracks You have some really big gaps in full message cover. That tells us possibly despite you getting messages, the secondary position ones aren't being fully decoded or received.

                They could be full of noise, or just plain out of range and not complete.

                Sent from my EML-L09 using Tapatalk
                Last edited by Oblivian; 2019-01-27, 22:33.
                Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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                • #9
                  And I've not seen a report to say otherwise since. But since the new uploader is capable of analysis due to keeping the 'quality' of data fr24 strive for we discovered there appears to be some unpublished/unspoken/unknown bundling of data before send.

                  This likely has thresholds as to how long a contact has been lost/last heard from. And when to ignore it if not producing data within these thresholds

                  So although locally you can see data, it may never be reflected after the capture and upload.

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                  Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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                  • #10
                    I'm not sure what "hits" are on flightradar24 to be honest. Maybe you have a lot of noise that is wrongly decoded as preambles but the messages are garbage.

                    What kind of setup of antenna / dongle are you using?
                    (If you have a lot of noise and in general to improve reception a specialized LNA is very good: https://www.rtl-sdr.com/new-product-...mhz-ads-b-lna/ )

                    Are you above the trees or hills of the area?

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                    • #11
                      Got some of my terminology wrong when referring to them saving BW and removing

                      From windows feeder (which in some ways is better than the pi as you can see constant data status)

                      The stream sync appears to be a realtime data down/up channel check
                      You can see it remove overlapping data

                      Code:
                      [bs][i]Client disconnected, 2 left
                      [feed][i]sent 9,0 AC
                      [feed][i]sent 9,0 AC
                      [feed][i]sent 9,0 AC
                      [feed][n]syncing stream async: 1
                      [feed][n]syncing stream result: 1
                      [feed][i]sent 10,0 AC
                      [feed][i]sent 10,0 AC
                      [feed][i]sent 10,0 AC
                      [feed][i]sent 10,0 AC
                      [feed][i]sent 10,0 AC
                      [feed][i]sent 10,0 AC
                      [feed][i]filtering out 1 overlapping AC (saving bandwidth)
                      [feed][i]sent 9,1 AC
                      And unknown reasons, removing others

                      Code:
                      [feed][i]sent 13,0 AC
                      [feed][i]sent 13,0 AC
                      [feed][i]removed 1 of 15 AC
                      [feed][i]sent 14,0 AC
                      [feed][i]sent 15,0 AC
                      [feed][i]sent 15,0 AC
                      [feed][i]sent 15,0 AC
                      And then the occasional stats update

                      Code:
                      [stats][e]Cached feed_id=5001 for network T
                      [stats][i]sent 2684 bytes
                      [feed][i]sent 13,0 AC
                      And for whatever reason, occasional errors

                      send - failed to send 12 + 516 bytes in mode 0, code -1: No error
                      Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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                      • #12
                        Originally posted by wiedehopf View Post
                        I'm not sure what "hits" are on flightradar24 to be honest. Maybe you have a lot of noise that is wrongly decoded as preambles but the messages are garbage.

                        What kind of setup of antenna / dongle are you using?
                        (If you have a lot of noise and in general to improve reception a specialized LNA is very good: https://www.rtl-sdr.com/new-product-...mhz-ads-b-lna/ )

                        Are you above the trees or hills of the area?
                        I am using the yellow flightaware pro stick at the moment. But I have a radarscape on order. The antenna is a "A3 ADS-B antenna, mounted about 1,5M above the highest point on the house. BUT there is a dual bander (2M / 70CM) antenna about 1 meter from the ADS-B antenna which is slightly higher than the ADS-B antenna. But it has NOT been transmissions on this antenna during these days.

                        And today (monday) is the same. LOT of hits, but few positions, compared to other receivers in the area. Something is definitly wrong. I think I will have to try the Jetvision DVB-T stick and see if that is better. It has been snow weather the last days, so I am thinking about static can have done some damage to the flightaware stick ?

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                        • #13
                          You can always recheck the gain to squeeze more out (thread with how to adjust gain about somehere)

                          But yes, static can zap components.


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                          Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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                          • #14
                            Originally posted by Talle View Post
                            And today (monday) is the same. LOT of hits, but few positions, compared to other receivers in the area. Something is definitly wrong. I think I will have to try the Jetvision DVB-T stick and see if that is better. It has been snow weather the last days, so I am thinking about static can have done some damage to the flightaware stick ?
                            I guess there are not many flights north of you, are there?
                            The radarcape is quite a bit better at coping with mobile phone and TV signal noise. (The ModeS Beast is probably the quite a bit cheaper receiver only part that is built in to the Radarcape, but the Radarcape does have a nice GPS clock coupled into the receiver)

                            The yellow Flightaware stick really needs a filter probably.
                            If you can shell out the money for a radar cape and want to experiment, try a rtl-sdr dongle v3 + their 1090 MHz LNA. (The LNA has 3 filters, copes very well with noise)
                            (https://www.rtl-sdr.com/new-product-...mhz-ads-b-lna/)
                            Also i would probably recommend another sd-card image for the pi, you can still install FR24 and other feeders, check out this excellent guide well worth a read:
                            https://discussions.flightaware.com/t/bake-a-pi/19886

                            The other antenna on the roof should at most block a small portion of the sky but nothing more.

                            Probably you just have LTE or other mobile phone signals messing with your reception, if you want to check the power spectrum with the dongle, that's also possible:
                            https://discussions.flightaware.com/...a-filter/27833

                            Good luck and i'm pretty sure you will have excellent reception with the Radarcape. (Also very good filtering)

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                            • #15
                              Ahem...

                              https://forum.flightradar24.com/showthread.php?t=11450

                              (Don't always need to head off forum to the competitor for help )

                              Sent from my EML-L09 using Tapatalk
                              Last edited by Oblivian; 2019-01-28, 08:37.
                              Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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